ALSA project - the C library reference
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Defines | |
#define | SND_USE_CASE_VERB_INACTIVE "Inactive" |
#define | SND_USE_CASE_VERB_HIFI "HiFi" |
#define | SND_USE_CASE_VERB_HIFI_LOW_POWER "HiFi Low Power" |
#define | SND_USE_CASE_VERB_VOICE "Voice" |
#define | SND_USE_CASE_VERB_VOICE_LOW_POWER "Voice Low Power" |
#define | SND_USE_CASE_VERB_VOICECALL "Voice Call" |
#define | SND_USE_CASE_VERB_IP_VOICECALL "Voice Call IP" |
#define | SND_USE_CASE_VERB_ANALOG_RADIO "FM Analog Radio" |
#define | SND_USE_CASE_VERB_DIGITAL_RADIO "FM Digital Radio" |
#define | SND_USE_CASE_DEV_NONE "None" |
#define | SND_USE_CASE_DEV_SPEAKER "Speaker" |
#define | SND_USE_CASE_DEV_LINE "Line" |
#define | SND_USE_CASE_DEV_HEADPHONES "Headphones" |
#define | SND_USE_CASE_DEV_HEADSET "Headset" |
#define | SND_USE_CASE_DEV_HANDSET "Handset" |
#define | SND_USE_CASE_DEV_BLUETOOTH "Bluetooth" |
#define | SND_USE_CASE_DEV_EARPIECE "Earpiece" |
#define | SND_USE_CASE_DEV_SPDIF "SPDIF" |
#define | SND_USE_CASE_DEV_HDMI "HDMI" |
#define | SND_USE_CASE_MOD_CAPTURE_VOICE "Capture Voice" |
#define | SND_USE_CASE_MOD_CAPTURE_MUSIC "Capture Music" |
#define | SND_USE_CASE_MOD_PLAY_MUSIC "Play Music" |
#define | SND_USE_CASE_MOD_PLAY_VOICE "Play Voice" |
#define | SND_USE_CASE_MOD_PLAY_TONE "Play Tone" |
#define | SND_USE_CASE_MOD_ECHO_REF "Echo Reference" |
#define | SND_USE_CASE_TQ_MUSIC "Music" |
#define | SND_USE_CASE_TQ_VOICE "Voice" |
#define | SND_USE_CASE_TQ_TONES "Tones" |
Functions | |
char * | snd_use_case_identifier (const char *fmt,...) |
Create an identifier. | |
int | snd_use_case_free_list (const char *list[], int items) |
Free a string list. | |
int | snd_use_case_get_list (snd_use_case_mgr_t *uc_mgr, const char *identifier, const char **list[]) |
Obtain a list of entries. | |
int | snd_use_case_get (snd_use_case_mgr_t *uc_mgr, const char *identifier, const char **value) |
Get current - string. | |
int | snd_use_case_geti (snd_use_case_mgr_t *uc_mgr, const char *identifier, long *value) |
Get current - integer. | |
int | snd_use_case_set (snd_use_case_mgr_t *uc_mgr, const char *identifier, const char *value) |
Set new. | |
int | snd_use_case_mgr_open (snd_use_case_mgr_t **uc_mgr, const char *card_name) |
Open and initialise use case core for sound card. | |
int | snd_use_case_mgr_reload (snd_use_case_mgr_t *uc_mgr) |
Reload and re-parse use case configuration files for sound card. | |
int | snd_use_case_mgr_close (snd_use_case_mgr_t *uc_mgr) |
Close use case manager. | |
int | snd_use_case_mgr_reset (snd_use_case_mgr_t *uc_mgr) |
Reset use case manager verb, device, modifier to deafult settings. |
The ALSA Use Case manager interface. See ALSA Use Case Interface page for more details.
ALSA Use Case Interface
The use case manager works by configuring the sound card ALSA kcontrols to change the hardware digital and analog audio routing to match the requested device use case. The use case manager kcontrol configurations are stored in easy to modify text files.
An audio use case can be defined by a verb and device parameter. The verb describes the use case action i.e. a phone call, listening to music, recording a conversation etc. The device describes the physical audio capture and playback hardware i.e. headphones, phone handset, bluetooth headset, etc.
It's intended clients will mostly only need to set the use case verb and device for each system use case change (as the verb and device parameters cover most audio use cases).
However there are times when a use case has to be modified at runtime. e.g.
o Incoming phone call when the device is playing music o Recording sections of a phone call o Playing tones during a call.
In order to allow asynchronous runtime use case adaptations, we have a third optional modifier parameter that can be used to further configure the use case during live audio runtime.
This interface allows clients to :-
o Query the supported use case verbs, devices and modifiers for the machine. o Set and Get use case verbs, devices and modifiers for the machine. o Get the ALSA PCM playback and capture device PCMs for use case verb, use case device and modifier. o Get the TQ parameter for each use case verb, use case device and modifier. o Get the ALSA master playback and capture volume/switch kcontrols for each use case.
#define SND_USE_CASE_DEV_BLUETOOTH "Bluetooth" |
Bluetooth Device
#define SND_USE_CASE_DEV_EARPIECE "Earpiece" |
Earpiece Device
#define SND_USE_CASE_DEV_HANDSET "Handset" |
Handset Device
#define SND_USE_CASE_DEV_HDMI "HDMI" |
HDMI Device
#define SND_USE_CASE_DEV_HEADPHONES "Headphones" |
Headphones Device
#define SND_USE_CASE_DEV_HEADSET "Headset" |
Headset Device
#define SND_USE_CASE_DEV_LINE "Line" |
Line Device
#define SND_USE_CASE_DEV_NONE "None" |
None Device
#define SND_USE_CASE_DEV_SPDIF "SPDIF" |
SPDIF Device
#define SND_USE_CASE_DEV_SPEAKER "Speaker" |
Speaker Device
#define SND_USE_CASE_MOD_CAPTURE_MUSIC "Capture Music" |
Capture Music Modifier
#define SND_USE_CASE_MOD_CAPTURE_VOICE "Capture Voice" |
Capture Voice Modifier
#define SND_USE_CASE_MOD_ECHO_REF "Echo Reference" |
Echo Reference Modifier
#define SND_USE_CASE_MOD_PLAY_MUSIC "Play Music" |
Play Music Modifier
#define SND_USE_CASE_MOD_PLAY_TONE "Play Tone" |
Play Tone Modifier
#define SND_USE_CASE_MOD_PLAY_VOICE "Play Voice" |
Play Voice Modifier
#define SND_USE_CASE_TQ_MUSIC "Music" |
TQ - Tone Quality
The interface allows clients to determine the audio TQ required for each use case verb and modifier. It's intended as an optional hint to the audio driver in order to lower power consumption. Music Tone Quality
#define SND_USE_CASE_TQ_TONES "Tones" |
Tones Tone Quality
#define SND_USE_CASE_TQ_VOICE "Voice" |
Voice Tone Quality
#define SND_USE_CASE_VERB_ANALOG_RADIO "FM Analog Radio" |
FM Analog Radio Verb
#define SND_USE_CASE_VERB_DIGITAL_RADIO "FM Digital Radio" |
FM Digital Radio Verb
#define SND_USE_CASE_VERB_HIFI "HiFi" |
HiFi Verb
#define SND_USE_CASE_VERB_HIFI_LOW_POWER "HiFi Low Power" |
HiFi Low Power Verb
#define SND_USE_CASE_VERB_INACTIVE "Inactive" |
Inactive Verb
#define SND_USE_CASE_VERB_IP_VOICECALL "Voice Call IP" |
Voice Call IP Verb
#define SND_USE_CASE_VERB_VOICE "Voice" |
Voice Verb
#define SND_USE_CASE_VERB_VOICE_LOW_POWER "Voice Low Power" |
Voice Low Power Verb
#define SND_USE_CASE_VERB_VOICECALL "Voice Call" |
Voice Call Verb
int snd_use_case_free_list | ( | const char * | list[], |
int | items | ||
) |
Free a string list.
list | The string list to free |
items | Count of strings |
int snd_use_case_get | ( | snd_use_case_mgr_t * | uc_mgr, |
const char * | identifier, | ||
const char ** | value | ||
) |
Get current - string.
uc_mgr | Use case manager |
identifier | |
value | Value pointer |
Note: String is dynamically allocated, use free() to deallocate this string.
Known identifiers: NULL - return current card _verb - return current verb
[=]{NAME}[/[{modifier}|{/device}][/{verb}]]
Recommended names for values: TQ - Tone Quality PlaybackPCM - full PCM playback device name CapturePCM - full PCM capture device name PlaybackCTL - playback control device name PlaybackVolume - playback control volume ID string PlaybackSwitch - playback control switch ID string CaptureCTL - capture control device name CaptureVolume - capture control volume ID string CaptureSwitch - capture control switch ID string PlaybackMixer - name of playback mixer PlaybackMixerID - mixer playback ID CaptureMixer - name of capture mixer CaptureMixerID - mixer capture ID
uc_mgr | Use case manager |
identifier | |
value | Value pointer |
Note: String is dynamically allocated, use free() to deallocate this string.
int snd_use_case_get_list | ( | snd_use_case_mgr_t * | uc_mgr, |
const char * | identifier, | ||
const char ** | list[] | ||
) |
Obtain a list of entries.
uc_mgr | Use case manager (may be NULL - card list) |
identifier | (may be NULL - card list) |
list | Returned allocated list |
Defined identifiers: NULL - get card list (in pair cardname+comment) _verbs - get verb list (in pair verb+comment) _devices[/{verb}] - get list of supported devices (in pair device+comment) _modifiers[/{verb}]- get list of supported modifiers (in pair modifier+comment) TQ[/{verb}] - get list of TQ identifiers _enadevs - get list of enabled devices _enamods - get list of enabled modifiers
_supporteddevs/{modifier}|{device}[/{verb}] - list of supported devices _conflictingdevs/{modifier}|{device}[/{verb}] - list of conflicting devices Note that at most one of the supported/conflicting devs lists has any entries, and when neither is present, all devices are supported.
uc_mgr | Use case manager (may be NULL - card list) |
identifier | (may be NULL - card list) |
list | Returned allocated list |
int snd_use_case_geti | ( | snd_use_case_mgr_t * | uc_mgr, |
const char * | identifier, | ||
long * | value | ||
) |
Get current - integer.
uc_mgr | Use case manager |
identifier | |
value | result |
Known identifiers: _devstatus/{device} - return status for given device _modstatus/{modifier} - return status for given modifier
uc_mgr | Use case manager |
identifier |
char* snd_use_case_identifier | ( | const char * | fmt, |
... | |||
) |
Create an identifier.
fmt | Format (sprintf like) |
... | Optional arguments for sprintf like format |
int snd_use_case_mgr_close | ( | snd_use_case_mgr_t * | uc_mgr | ) |
Close use case manager.
uc_mgr | Use case manager |
uc_mgr | Use case manager |
int snd_use_case_mgr_open | ( | snd_use_case_mgr_t ** | uc_mgr, |
const char * | card_name | ||
) |
Open and initialise use case core for sound card.
uc_mgr | Returned use case manager pointer |
card_name | Sound card name. |
Open and initialise use case core for sound card.
uc_mgr | Returned use case manager pointer |
card_name | name of card to open |
int snd_use_case_mgr_reload | ( | snd_use_case_mgr_t * | uc_mgr | ) |
Reload and re-parse use case configuration files for sound card.
uc_mgr | Use case manager |
Reload and re-parse use case configuration files for sound card.
uc_mgr | Use case manager |
int snd_use_case_mgr_reset | ( | snd_use_case_mgr_t * | uc_mgr | ) |
Reset use case manager verb, device, modifier to deafult settings.
uc_mgr | Use case manager |
Reset use case manager verb, device, modifier to deafult settings.
uc_mgr | Use case manager |
int snd_use_case_set | ( | snd_use_case_mgr_t * | uc_mgr, |
const char * | identifier, | ||
const char * | value | ||
) |
Set new.
uc_mgr | Use case manager |
identifier | |
value | Value |
Known identifiers: _verb - set current verb = value _enadev - enable given device = value _disdev - disable given device = value _swdev/{old_device} - new_device = value
uc_mgr | Use case manager |
identifier | |
value | Value |